The present invention relates generally to the field of visual copyright protection. More specifically, the present invention relates to the generation of optical signals that impede the ability of recording devices to make copies of the content.
It is a known problem that pirates videotape content for which they have no rights such as movies, concerts, and proprietary events. Often, copies of these recordings are sold for profit by the pirates or distributed for free (for example, over the internet), depriving revenue to the rightful owners of the content. To date, no methods and apparatuses have been commercially utilized to protect this content from being effectively recorded.
The following terms are useful in discussing visual image generation and disruption.                UV—Ultraviolet light whose frequency is greater than or equal to 0.200 nm and less than or equal to 0.400 um.        VIS—Visible light whose frequency is greater than or equal to 0.400 nm and less than or equal to 0.700 um.        NIR—Near infrared light whose frequency is greater than or equal to 0.700 nm and less than or equal to 1.400 um.        NVIS—Non visible light whose frequency is less than 0.400 um or greater than 0.700 um.        Content—Any optical information created for presentation to either a human eye or recording device.        IRD—Any image recording device capable of recording single or multiple optical images such as a camcorder, digital camera, or film camera.        IGD—Any image generating device capable of generating an optical image including film projectors, monitors, displays, spot lights, and other lighting devices. Some technologies used by IGD's may include LCD's, MEM's, IDLA's, and optical irises.        
One previously discussed solution involves blasting a movie theater audience with a constant source of infrared light. This blasted light has such intensity that it washes out the visible light in any image recorded by an IRD. A serious drawback to this solution is that IRDs may be fitted with infrared filters to filter out this constant infrared signal.
There is sufficient evidence in the prior art that solving piracy of content is a serious issue. A series of patents have addressed the problem of preventing video reproduction through the modification of electronic video signals. Other patents address the issue of preventing the copying of paper based and photographic content. Further, several patents deal with the issue of limiting access to multimedia content. Other patents deal with adding watermarks to content to later prove that copying has taken place. All of this prior art is trying to solve the serious problem of illegal piracy of content. There is still a need to solve the serious problem of piracy of content such as movies in theaters, live performances, and protected areas by IRDs and other electronic image detecting devices.
U.S. Pat. No. 3,963,865, entitled “Anti-Piracy Method and System” to Songer discloses a method and system for eliminating or deterring the unauthorized duplication or piracy of video program material, including video tape, cable and broadcast television material. Songer's patent does not address the parallel problem of eliminating or deterring the unauthorized duplication or piracy of optical program material, including movie presentations in theaters, presentations of live content such as concerts, or pieces of art on display in museums. Songer '865 attempts to thwart piracy by encoding a composite video signal when recording content. The encoding method allows normal playback of the content on televisions, but prevents the content from being effectively rerecorded or duplicated on commercial recorders by distorting the recording and thereby destroying its commercial value. Similarly, an optical system to thwart piracy is needed whereby the optical content may be viewed normally when first presented but prevents the content from being effectively rerecorded or duplicated on commercial recorders by distorting the recording and thereby destroying its commercial value.
U.S. Pat. No. 4,631,603 entitled “Method and Apparatus for Processing a Video Signal so as to Prohibit the Making of Acceptable Video Tape Recordings Thereof” to Ryan discloses an invention which modifies a video signal so that a television receiver will still provide a normal color picture from the modified video signal while a videotape recording of the modified video signal produces generally unacceptable pictures. Like the Songer patent, this patent evidences the need for protecting content from pirates. The present invention also addresses the need to protect content from pirates. The Ryan patent seeks to prevent pirates from copying video content through hard wiring copying methods. The present invention prevents pirates from copying displayed content optically using IRDs.
An example of a device which attempts to limit access to copyrighted content is disclosed in U.S. Pat. No. 5,907,656 entitled “Apparatus and Method for Reproducing Video Signals with Varying-Magnitude AGC Signals” to Oguro. This patent disclosed a signal format and compatible reproducing apparatus which uses the disclosed signal format to protect the copyright of recorded video and audio data against dubbing. This patent requires that both the signal and the hardware used to duplicate the copyrighted content be compliant with the system disclosed. Needed is a copy protection scheme which is independent from compliant hardware on the part of the pirate.
U.S. Pat. No. 5,680,454 entitled “Method and System for Anti-Piracy Using Frame Rate Dithering” to Mead discloses a method and system of displaying an image sequence containing a plurality of image frames to inhibit an unauthorized duplication thereby by a camera by varying the frame rate in dependence upon a pseudo-random noise sequence about a nominal frame rate. This patent attempts to prevent pirates from duplicating a displayed sequence by slightly modifying the frame rate of the displayed sequence, thus making it difficult for the pirates' IRD to synchronize with the displayed sequence. This method may not work with new IRDs whose electronics are much more sophisticated and are capable of synchronizing automatically to slightly varying frame rates. In post-processing the resultant luminescence change is also easily removable using modern video editing tools. Also pseudo random changes in frequency may be easily perceived by humans. In addition, this method affects the displayed image globally, not allowing for selective modifications of an image where effects are most likely to be advantageous. Further, this patent does not disclose a system that may prevent the recording of live performances or protected areas.
Needed is a way to protect content from unauthorized, high quality copying by IRDs, while minimizing human perceivable defects. Such a system should prevent a modern IRD or other types of electronic optical detection systems from recording optically displayed images in whole and in part, and similarly prevent the recording of live performances or protected areas.